The first order of reading has got to be Brad Templeton's [Copyright Myth's Explained].
A good introduction to copyright law is [Copyright Basics] at IP Watchdog.
[The US Copyright Office] of course contains the current law in the US.
[Fan Fiction, Novels, Copyright, and Ethics] by Michela Ecks will probably cause some confusion, but nevertheless should give one an idea as to the broad range of policies and opinions of what literary authors will tolerate. Buried within this article was a link to [Writers University Database] which contains a list of contemporary authors and their policies on fan fiction if known.
Intellectual property protection comes in a number of flavors.